1. Field of the Invention
The present invention relates to a process for the manufacture of 1,1,1,3,3-pentachloropropane.
2. Description of the Related Art
The Montreal Protocol of 1987 placed a ban on certain substances that deplete the ozone layer, especially chlorofluorocarbons (CFC""s). To hasten the elimination of CFC production and use, the Protocol allowed for certain fluorocarbon products (HCFC""s) to be used as xe2x80x9cbridge replacements.xe2x80x9d Although these bridge replacements are considerably more ozone friendly than CFC""S, they are intended to be transitional and not permanent replacements. Fluorocarbon producers are actively pursuing replacement candidates known as xe2x80x9cthird generation fluorocarbons.xe2x80x9d These third genera-tion fluorocarbons will require hydrochlorocarbon feedstocks.
The second largest U.S. fluorochemical end-use market, next to refrigeration, is for blowing agents utilized in the manufacture of various synthetic plastic formed products. CFC-1 1 was the dominant product in this market, however, it has been replaced by the bridge-fluorocarbon HCFC-141b. Because foam manufacturers must transition away from HCFC-141b by 2003, new third generation fluorocarbon products must be developed and commercialized.
Several fluorochemical producers have targeted fluorocarbon 1,1,1,3,3-pentafluoropropane, utilizing 1,1,1,3,3-pentachloropropane as the hydrochlorocarbon feedstock, as the primary replacement product for foam blowing applications. Zil""bennan et.al. (xe2x80x9cSynthesis of liquid telomers of vinyl chloride with carbon tetrachloridexe2x80x9d, J Org. Chem. USSR (English Transl.), 3:2101-2105,1967)prepared 1,1,1,3,3-pentachloropropane in a 58% yield by the reaction of carbon tetrachloride and vinyl chloride using ferrous chloride tetrahydrate in isopropanol. In addition, Kotora et.al (xe2x80x9cAddition of tetrachloromethane to halogenated ethenes catalyzed by transition metal complexesxe2x80x9d, J Mol. Catal., 77(1):51-60,1992) prepared 1,1,1,3,3-pentachloropropane in high yields using either CuCl/C4H9NH2 or Ru(Ph3P)3.
European Patent Application No. 131561 describes a very general process for the addition of a haloalkane to an alkene or alkyne compound in the presence of iron metal and a phosphorus(V) compound. While EP 131561 is very general in nature, several examples are set forth on the batch reaction of ethylene and carbon tetrachloride to produce 1,1,1,3-tetrachloropropane. However, EP 131561 does mention a wide variety of olefins and alkynes, including vinyl halides. EP 131561 also mentions that the batch process could be made continuous, but does not include any specifics on how this would be carried out.
Despite the known processes, improvements are needed in the manufacture of 1,1,1,3,3-pentachloro-propane. The present invention is directed to such an improved process. More particularly, the present invention relates to the addition of water to enhance production of 1,1,1,3,3-pentachloropropane.
It is an object of the present invention to provide an improved process for the production of chlorinated or hydrochlorinated alkanes. More particularly, a process is provided by which addition of water is used to enhance the production of any hydrochlorocarbon feedstock through the use of Kharasch chemistry, i.e., the combination of a polychlorinated alkane with an olefin to produce a chlorinated or hydrochlorinated alkane.
In one aspect, the invention provides a process for the production of a chlorinated or hydrochlorinated alkane by the reaction of a polychlorinated alkane and an olefin in a reactor, wherein water is added in an amount sufficient to increase the rate of the reaction.
In another aspect, the invention provides a process for the production of 1,1,1,3,3-pentachloropropane by the reaction of carbon tetrachloride and vinyl chloride in a reactor, wherein water is added in an amount sufficient to increase the rate of the reaction.